This invention relates to an improvement of the inking device of a printing machine and more particularly adjusting means for the amount of ink to be used.
FIG. 1 shows a conventional inking device of a printing machine, in which there is disposed a support 3 for supporting, through a mounting block 4, a doctor knife 2, one edge of which is positioned closely to the outer peripheral surface of an inking roller 1. The mounting block 4 is mounted on the support 3 by a plurality of bolts, not shown, and is fixed integrally to the doctor knife 2. A plurality of cam levers 5 are pivotally connected to the support 3 by pins 6 and the top surfaces of the cam levers 5 contact the doctor knife 2 to adjust the gap between the doctor knife 2 and the inking roller 1. The front ends of adjusting screws 7 screwed through the support 3 abut against the back surfaces of the cam levers 5 respectively so as to slightly rotate the cam levers by rotating the screws 7.
Accordingly, in the case where it is required to adjust the amount of the ink to be used, an operator had to rotate the adjusting screws 7 to rotate clockwisely or anti-clockwisely the cam levers 5 about the pins 6 thereby slightly approaching or separating the front edge of the doctor knife to and from the inking roller 1, whereby the gap therebetween can be adjusted.
However, with the conventional construction described above, the amount of the ink in the inking device to be used had to be adjusted manually by controlling the adjusting screws 7, and moreover, the operator could not judge whether a suitable amount of ink was applied on a printing matter or not until the printed matter reaches a collecting portion of the printed matters where the operator can inspect them. If the ink amount was not suitable for the printed matter, the operator had to readjust the adjusting screw. Thus, in the conventional inking device of a printing machine, the adjustment of the ink involved much time, and labour of the operator and loss of printed matters.
Furthermore, since the doctor knife 2 is made of a thin plate, the doctor knife 2 is often deformed by the rotation of the inking roller 1 and the viscosity of the ink 14, thereby changing the gap between the knife 2 and the roller 1. This affects adversely printed matters.